SPT is an enzyme that catalyzes the reaction through which L-serine and palmitoyl coenzyme A are condensed to synthesize 3-ketodihydrosphingosine, and is involved in the biosynthesis of sphingolipids. SPT is constituted by a plurality of subunits. 3 types of SPT subunits are known: SPT1 (also called SPTLC1), SPT2 (also called SPTLC2) and SPT3 (also called SPTLC3). From the perspective of a complex of subunits, a complex consisting of subunits SPT1 and SPT2 and a complex consisting of subunits SPT1 and SPT3 are known as SPT.
The sphingolipids include ceramide, sphingomyelin, ganglioside and the like. The sphingolipids are constituents of cell membranes and are known to play an important role in maintenance of homeostasis of the membranes and signal transduction while having various physiological activities. Myriocin, which has an inhibitory effect on SPT, is known to inhibit the growth of activated lymphocytes, to inhibit the growth of mouse melanoma cell lines, and to exhibit an antitumor effect on mouse melanoma tumor models (Non Patent Literature 1).
Compounds described in Patent Literatures 1 to 6, etc., have been known so far as compounds having an antitumor effect.